Investigating judges at the Khmer Rouge tribunal on Tuesday rejected an appeal from the UN prosecutor, who had requested they continue investigating a controversial third case at the court.

The prosecutor, Andrew Cayley, said in an earlier submission to the investigating judges that they had failed to investigate key crime sites and had not interviewed the two suspects of the case, No. 003.

The judges, Siegfried Blunk and You Bunleng, said in a public statement Tuesday that Cayley’s requests were “invalid.”

The rejection was one in a line of contentious statements shared between the two parts of the court, following the two judges’ announcement in April they had concluded their investigation. The judges have also ordered Cayley to retract portions of a public statement involving Case 003, claiming he had divulged confidential court information.

Cayley has refused to retract his statements in a formal appeal to the court, and he told VOA Khmer by e-mail on Tuesday he plans to appeal the judges’ latest decision not to further investigate Case 003.

The UN-backed court has come under increased scrutiny over that case and another, No. 004, because Prime Minister Hun Sen and a number of Cambodian judges have publicly objected to them.

Meanwhile, observers say the two cases could go far in fulfilling the court’s mandate to try as many Khmer Rouge leaders as possible, bringing to 10 the total number prosecuted under the court.

So far the court has only managed to conclude one trial, the relatively simple case against Kaing Kek Iev, the chief of Tuol Sleng prison. A trial against four more Khmer Rouge leaders is expected later this year.